Tag Archives: albedo

Climate change is making the Earth dimmer, which, in turn, warms up the climate

In an unexpected turn of events, climate change seems to be making the Earth a little bit dimmer, according to new research.

Image credits Arek Socha.

One of the properties that define planets throughout space is their ‘albedo’. Multiple different elements factor into this property which, in its simplest definition, is the measure of how much incoming light a planetary body reflects. A planet’s albedo can thus have a significant effect on environmental conditions across its surface.

But the opposite is also true, and climate conditions on the surface can influence a planet’s overall albedo. New research explains that climate change is already affecting Earth’s albedo, causing a significant drop in our planet’s ability to reflect light over the last 20 years or so.

No beam-back

“The albedo drop was such a surprise to us when we analyzed the last three years of data after 17 years of nearly flat albedo,” said Philip Goode, a researcher at New Jersey Institute of Technology and the lead author of the new study.

The authors worked with earthshine data recorded by the Big Bear Solar Observatory in Southern California from 1998 to 2017. Satellite readings of earthshine over the same timeframe were also used in the study. Earthshine is the light reflected from the Earth into space, and it is what makes the Moon so bright in the night’s sky.

All in all, the team reports, the Earth is beaming back roughly one-half of a watt less per square meter of its surface than it did 20 years ago. For perspective, the typical lightbulb uses around 60 watts. A single LED uses around 0.015 watts. The authors explain that it’s equivalent to a 0.5% decrease in the Earth’s reflectance.

The two main components deciding how much sunlight reaches the Earth are how bright the Sun shines, and how reflective our planet is. But the team reports that the drop in albedo they’ve observed did not correlate with any periodic changes in the Sun’s brightness — meaning that the drop was caused entirely by changes in how reflective the Earth is.

This drop is mostly powered by warming ocean waters. The authors point to a reduction in bright, reflective low-lying clouds over the eastern Pacific Ocean over the last two decades, as shown by measurements taken as part of NASA’s Clouds and the Earth’s Radiant Energy System (CERES) project. Sea surface temperature increases have been recorded in this area following the reversal of the Pacific Decadal Oscillation (PDO).

A dimmer Earth means that the planet is absorbing much more of the incoming solar energy into Earth’s climate systems. Here, it’s likely to contribute to global warming. The authors estimate that this extra sunlight is on the same magnitude as the sum of anthropogenic climate forcing over the last two decades.

“It’s actually quite concerning,” said Edward Schwieterman, a planetary scientist at the University of California at Riverside who was not involved in the new study. For some time, many scientists had hoped that a warmer Earth might lead to more clouds and higher albedo, which would then help to moderate warming and balance the climate system, he said. “But this shows the opposite is true.”

The paper “Earth’s Albedo 1998–2017 as Measured From Earthshine” has been published in the journal Geophysical Research Letters.


What is the Greenhouse effect, and why it’s (currently) bad for us

A lot of ink has been spilled on climate change and the effect of greenhouse gases emissions lately. And for good reason. But how do some gases make the planet warmer? What is the link between CO2 and the climate? Let’s find out.


Image credits orvalrochefort / Flickr.

How it all starts

With precious few exceptions, all the energy on Earth derives from the sun. Sunlight carries this energy (mostly in the form of heat, visible light, and radiation that we cannot perceive) from the fusing nuclei in the star’s core to our planet’s surface.

Part of this energy keeps our planet alive. Winds blow to appease pressure differences in the atmosphere, which are caused by differences in temperature. Plants gobble up sunlight to fuse carbon to hydrogen in photosynthesis. Even the coal and oil we burn are akin to chemical batteries storing the sun’s energy.

Part of that input of energy, however, doesn’t stay here. It gets reflected — by clouds, oceans, plants, ice caps — back into space. While every other celestial body out there does this, each will differ in how much of the incoming energy it reflects. This ratio of incoming energy to reflected energy is known as a planet’s ‘albedo‘, from the Latin word for ‘white’. Albedo is measured on a scale from 0 (no reflection) to 1 (complete reflection), and the Earth currently sits at about 0.30 on the albedo scale (measured in the 1970s), meaning it reflects some 30% of all incoming sunlight.

To summarise, conditions on a planet’s surface depend on a tug of war between the energy output of its host star and the planet’s capacity to reflect or capture it.

What is the greenhouse effect?

The greenhouse effect is caused by greenhouse gases in the atmosphere preventing heat from radiating out into space. When trapped heat radiates out of the surface, these gases absorb and contain energy inside the atmosphere.

Greenhouse effect.

Image via Pixabay.

While albedo reflects incoming sunlight and the energy it carries away from the surface of the Earth, its atmosphere works as a temperature battery. Clouds reflect about 23% of incoming solar energy, but they — alongside the rest of the atmosphere — also absorb roughly the same amount, 23%. What remains of the incoming solar energy is either reflected (7% of total) or absorbed (47%) by the surface.

Certain compounds in the atmosphere (most notably water vapor, carbon dioxide, and methane) are very good at absorbing heat (infrared radiation) and later emit it back out. Greenhouse gases capture most of that 23% of the incoming energy absorbed in the atmosphere.

All in all, we’re actually very lucky to have a plump atmosphere that contains some greenhouse gases — they help ‘spread’ energy around evenly. A planet like Mars, with its thin atmosphere, is plagued by temperatures of both extremes: scorching in the sunlight, freezing in the shadow. The same goes for Mercury — despite being the closest planet to the sun, nighttime temperatures here drop as low as -290° F(-180° C).

However, this is also where our climate troubles start. Greenhouse gases in the atmosphere absorb energy as long as their environment is at a higher energy state (they absorb infrared light when their environment is warmer than them). The atmosphere and surface, then, absorb most energy during the day and release most of it at night. These gases radiate energy in all directions, meaning some of that is released towards the Earth’s surface to be reabsorbed.

When they release it, some of the energy goes back into the ground. The higher the concentration of greenhouse gases in the atmosphere, the more energy gets trapped this way. Rinse and repeat enough times, and you get to where we are today — we’ve pumped so much CO2 into the atmosphere that it’s making a noticeable change in average temperatures.

Why is it a problem for us today?

Strictly speaking, climate change itself isn’t the problem — its consequences are.

For all our technology and know-how, society today is completely dependent on nature for its survival. We rely on natural processes to clean our water, fatten the fish we capture, pollinate our crops, generate the oxygen we need. We really enjoy the sea level staying where it is, and we’ve constructed various social and cultural mechanisms to adapt to the climatic and ecological particularities of the places we live in. Climate change — spurred on by the greenhouse gases we generate — threatens to destroy these natural systems we so dearly rely on.

When they change, we and our society will have to change as well, in order to survive. But the fact of the matter is that we have evolved, biologically and culturally, economically, and socially, to fit the mold our environments provided. Adapting to a post-climate-change world will entail social and economic upheaval the likes of which humanity has never faced before.

Another issue with the greenhouse effect, and by extension climate change, is that it has a lot of inertia. It takes time to fix. Even directly scrubbing CO2 out of the atmosphere will take time: there are roughly 3.200 gigatons of CO2 in Earth’s atmosphere right now (410 ppm), and we’d need to scrub out some 1.440 gigatons (45%) off that to get to pre-industrial levels.

This inertia is only compounded with respect to the effects of climate change. The world’s ecosystems will need time to recover even after greenhouse gas levels in the atmosphere have been reduced — and there’s no guarantee they’ll go back to being what they were. Every species lost clears an evolutionary niche that evolution will fill with something else. There’s no guarantee that ‘something else’ will be to our liking or be useful for us.

Finally, there is this spot of trouble:

The Greenhouse effect is self-enforcing

This is actually one of the greatest dangers facing humanity at the moment for a very simple reason: we’ve helped get it started, but greenhouse-type effects are perfectly capable of driving themselves on.

Annual Temperature Local.

Temperature map of regions where record highs (red) and lows (blue) were set in 2015, relative to the year before.
Image and caption credits Berkeley Earth / Wikimedia

Water vapor, for example, is a greenhouse gas, so it helps trap heat. Ice sheets are vast expanses of white, so they increase our planet’s albedo. A warmer climate will increase atmospheric concentrations of the first while reducing areas of the latter. The increase in greenhouse gases coupled with a reduction in albedo will warm the climate even more.

We are already seeing this positive feedback cycle at work. Warmer average temperatures, for example, are causing organic matter buried in permafrost to decompose, which releases carbon dioxide. The polar ice sheets are reeling and fragmenting under warmer conditions, reducing their ability to reflect energy back to space. These are just a few examples of how the greenhouse effect can get out of hand.

Cape Town in South Africa narrowly avoided running completely out of water after three years of relentless drought. The drought in California which ended last year was also spurred on by climate change. And there are things we just don’t know about.

“Large, abrupt climate changes have repeatedly affected much or all of the Earth, locally reaching as much as 10°C change in 10 years. Available evidence suggests that abrupt climate changes are not only possible but likely in the future, potentially with large impacts on ecosystems and societies,” reads the a consensus study report published by the National Research Council in 2002.

“We do not yet understand abrupt climate changes well enough to predict them.”

Taken to the extreme, like the state of Venus today shows, the cycle can repeat until our planet becomes a hot rock drenched in boiling acid. Not a pleasant prospect.

But, as the authors of the study themselves notes, “there is no need to be fatalistic; human and natural systems have survived many abrupt changes in the past, and will continue to do so. Nonetheless, future dislocations can be minimized by taking steps to face the potential for abrupt climate change.”

Climate change is making the Arctic red — and we should be very worried about it

You’ve heard of yellow snow, but there is another shade you should fear even more: called pink, red or watermelon snow, researchers warn that this phenomenon is a worrying testament of drastic melting in the Arctic.

Red snow algae.
Image credits Iwona Erskine-Kellie.

Red snow isn’t new. The phenomenon was observed by the first arctic explorers, and it was initially believed to be caused by iron oxides permeating the snow. Since then, however, it has been established that the hue is a product of red algae that bloom in frozen water. A new study published in the journal Nature Communications shows that these blooms are causing the snow to melt faster and they’re only going to grow more rapidly as climate change causes Arctic snow to melt more.

One property of snow is high albedo, meaning it reflects a large proportion of incoming light instead of absorbing it as heat. The study found that over a 100-day period, the algae-rich snow has a 13% lower albedo than white snow. The catch is that while these algae bloom naturally, man-made global warming puts them on a positive feedback loop — higher average temperatures mean more snow is melting each year, providing the water that algae feed on, which in turn cause the snow to melt.

“As we infer from our data, melting is one major driver for snow algal growth,” the study notes. “Extreme melt events like that in 2012, when 97% of the entire Greenland Ice Sheet was affected by surface melting, are likely to re-occur with increasing frequency in the near future as a consequence of global warming. Moreover, such extreme melting events are likely to even further intensify the effect of snow algae on surface albedo, and in turn melting rates.”

That’s because the glacier melt, disproportionately driven by the rise in global temperatures, is effectively watering the red algae, says lead study author Steffi Lutz of the University of Leeds.

“The algae need liquid water in order to bloom,” she said. “Therefore the melting of snow and ice surfaces controls the abundance of the algae. The more melting, the more algae. With temperatures rising globally, the snow algae phenomenon will likely also increase leading to an even higher bio-albedo effect.”

As temperatures continue to rise, the Artic will keep taking on a bloody shade. Maybe it’s allergic to climate change.

Scientists discover “new” craters on the Moon


Albedo map credit: NASA GSFC/SwRI Topographic map credit: NASA GSFC/ASU Jmoon

Albedo map credit: NASA GSFC/SwRI
Topographic map credit: NASA GSFC/ASU Jmoon

Understanding the Moon’s recent geological history is important and could put the entire solar system into perspective.

“These ‘young’ impact craters are a really exciting discovery,” said SwRI Senior Research Scientist Dr. Kathleen Mandt, who outlined the findings in a paper published by the journal Icarus. “Finding geologically young craters and honing in on their age helps us understand the collision history in the solar system.”

Using LAMP and LRO’s Mini-RF radar data, the team mapped the floors of very large, deep craters near the lunar south pole. The craters are very difficult to study because the Sun never illuminates them directly. However, tiny differences in the craters’ reflectivity (also called albedo) allows researchers to estimate their age.

“We study planetary geology to understand the history of solar system formation,” said SwRI’s Dr. Thomas Greathouse, LAMP deputy principal investigator. “It is exciting and extremely gratifying to happen upon a unique and unexpected new method for the detection and age determination of young craters in the course of nominal operations.”

Space collision played a key role in the solar system’s formation and history, including in the history of the Moon itself. The satellite is riddled with meteorite impact craters, and by dating the craters, the frequency and intensity of collision through time can also be understood. A press release from the Southwest Research Institute reads:

“When a small object collides with a larger object, such as the Moon, the impact creates a crater on the larger body. Craters can be a few feet in diameter or several miles wide. During the impact, the material ejected forms a blanket of material surrounding the crater. The ejecta blankets of “fresh,” relatively young craters have rough surfaces of rubble and a sprinkling of condensed, bright dust. Over millions of years, these features undergo weathering and become covered with layers of fluffy, dark dust.”

To make this discovery even more intriguing, the same technology could be used to study the craters on other objects.

“Discovering these two craters and a new way to detect young craters in the most mysterious regions of the Moon is particularly exciting,” said Mandt. “This method will be useful not only on the Moon, but also on other interesting bodies, including Mercury, the dwarf planet Ceres, and the asteroid Vesta.”

geological hacks

Climate change reversal hacks shunned in report. “Wake up and cut emission!”

Mitigating climate change is on the agenda of every world government, but somehow little is done to curb global warming. Echoing a quick-fix approach to life so predominantly engraved in modern culture, some are considering sweeping climate change under the proverbial rug. These so called geo-engineering methods aim to fix climate change by altering the environment, but those ideas that are actually practical today only mask the effects and do nothing to treat the symptoms, a new report signed by 16 top scientists reads. The authors used this opportunity to make an appeal for reducing global emissions, else we might be forced to actually engineer the planet with unforeseeable consequences.

Geo hacks not the way to go

geological hacks

Image: Sam Doust

A few years back, one British panel asked for immediate financial support into researching climate-altering interventions. The newly released twin report,  Climate Intervention: Carbon Dioxide Removal and Reliable Sequestration and Climate Intervention: Reflecting Sunlight to Cool the Earth, is much more skeptical and cautions on how the world should approach geo-engineering solutions, which can be extremely dangerous and might end up doing more harm than good. What’s important though is that these matters are being discussed and analyzed now, when there is still time to act. The alternative is to act in the heat of the moment, once climate change becomes too “hot” to ignore. As such, agencies backed by both government and private ventures, like Bill Gates’ foundation, are currently research the viability of these methods.  Still, relying on a planetary hack – instead of cutting carbon dioxide emissions – is “irresponsible and irrational”, the report said.

“That scientists are even considering technological interventions should be a wake-up call that we need to do more now to reduce emissions, which is the most effective, least risky way to combat climate change,” Marcia McNutt, the committee chair and former director of the US Geological Survey, said.

The report discusses at large some of these planetary hacks. The two most popular methods are carbon capture and sequestration (CCS), which basically involves siphoning CO2 from the atmosphere and storing it deep underground similarly to how some pilot coal-fired power plants are already doing, and albedo modification. The albedo is a scientific term that refers to how much sunlight is being reflected back in space. By injecting albedo altering chemicals in the upper atmosphere, like sulphur dioxide, more energy will be reflected and thus temperatures will be lower.

Albedo modification doesn’t lower CO2 concentration, however. The greenhouse gas will still remain in the atmosphere for centuries to come before it breaks down and, worse off, the method does nothing to curb ocean acidification. Up to 90% of all CO2 spewed into the atmosphere is absorbed by the planet’s oceans, causing a drop in pH severely affecting coral and plankton life, with spiraling consequences for the world’s ecosystems.

1. A million tons of sulfur dioxide would be needed to begin the cooling process. Luckily SO2, a byproduct of coal-burning power plants, is a common industrial chemical. 2. Inject it into the stratosphere. Load the sulfur dioxide into aircraft — converted 747s, military fighters, or even large balloons — and carry it up to the stratosphere. This will cost about $1 billion a year. 3. Wait for the chemical reaction. In a series of reactions, sulfur dioxide combines with other molecules in the atmosphere, ultimately forming sulfuric acid. This H2SO4 binds to water to form aerosol droplets that absorb and reflect back into space 1 to 3 percent of the sun's rays. (The particles also contribute to the depletion of the ozone layer, but scientists are researching alternate chemicals.) 4. Let the planet cool. Credit: Wired

1. A million tons of sulfur dioxide would be needed to begin the cooling process. Luckily SO2, a byproduct of coal-burning power plants, is a common industrial chemical. 2. Inject it into the stratosphere. Load the sulfur dioxide into aircraft — converted 747s, military fighters, or even large balloons — and carry it up to the stratosphere. This will cost about $1 billion a year. 3. Wait for the chemical reaction. In a series of reactions, sulfur dioxide combines with other molecules in the atmosphere, ultimately forming sulfuric acid. This H2SO4 binds to water to form aerosol droplets that absorb and reflect back into space 1 to 3 percent of the sun’s rays. (The particles also contribute to the depletion of the ozone layer, but scientists are researching alternate chemicals.) 4. Let the planet cool. Credit: Wired

Albedo intervention on a global scale, which seems to be viable according to computer models and real-life experience from volcanic eruptions, can also be dangerous on multiple levels. First, we might actually cool the planet more than we’d have to, secondly it’s unlikely that we can inject the sulfur compounds in a customized, distributed manner. Currents and wind gusts are too unpredictable for this to happen, so what might happen is some places will have a climate to their liking, but an African or Asian country might feel threatened because their rain patterns are now amok. Who should be in charge of spraying albedo modifying chemicals? How can smaller governments challenge a measure that affects the whole world? Conflicts and violence might arise. Overall, as you might have already guessed, the authors dismissed albedo intervention as absolutely nonviable.

“It’s hard to unthrow that switch once you embark on an albedo modification approach. If you walk back from it, you stop masking the effects of climate change and you unleash the accumulated effects rather abruptly,” Waleed Abdalati, a former Nasa chief scientist who was on the panel, said for The Guardian.

“The message is that reducing carbon dioxide emissions is by far the preferable way of addressing the problem,” said Raymond Pierrehumbert, a University of Chicago climate scientist, who served on the committee writing the report. “Dimming the sun by increasing the earth’s reflectivity shouldn’t be viewed as a cheap substitute for reducing carbon dioxide emissions. It is a very poor and distant third, fourth, or even fifth choice. |It is way down on the list of things you want to do.”

CO2 capture on the other hand is benign and is actually the way to go. Unfortunately, it costs so much to deploy at a scale where it might actually mitigate global warming that it’s completely unpractical at this point.

“I think there is a good case that eventually this might have to be part of the arsenal of weapons we use against climate change,” said Michael Oppenheimer, a climate scientist at Princeton University, who was not involved with the report.

Even so, compared to the albedo intervention, carbon sequestration is far ahead. The only problem with carbon sequestration is how much it costs, whereas the problem with albedo intervention is what might happen – we don’t know for sure!

“My view of albedo modification is that it is like taking pain killers when you need surgery for cancer,” said Pierrehumbert. “It’s ignoring the problem. The problem is still growing though and it is going to come back and get you.”